Income Taxes - Reconciliation of income tax benefit (provision) of the TRSs to the amount computed by applying the federal corporate tax rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Book loss for TRSs	$ 2,094	$ 5,254	$ 10,681
Tax at statutory rate on earnings from continuing operations before income taxes	712	1,786	3,632
Change in tax rates	(14,189)	0	0
State taxes	109	160	420
Other	(2,226)	(2,668)	(829)
Income tax (expense) benefit	$ (15,594)	$ (722)	$ 3,223